In this March 15, 2016 photo, a neonatal outcomes nurse swaddles a premature baby at Advocate Children's Hospital in Chicago.

M. Spencer Green
/ AP

Women who deliver children before 37 weeks of pregnancy are also more likely to have heart attacks, according to a new study from Magee-Women’s Research Institute.

Researchers followed 1,049 women for 25 years and found that women who had preterm births and a pattern of increasing blood pressure were also more likely to have greater calcium buildup in their hearts, putting them at higher risk for cardiovascular disease and heart attacks.

Epidemiologist Janet Catov, the study’s lead author, said it’s interesting that women who also had increasing blood pressure but gave birth to full-term babies didn’t have as much plaque in their arteries.

“We don’t know why, but there was something additional that this combination of increasing blood pressure and preterm birth history seemed to put women at higher risk,” she said.

In fact, for study volunteers who had full term births, Catov said calcium buildup could be explained by weight gain or smoking.

The study also found that black women were more likely than their white counterparts to have the risk factors of elevated blood pressure and give birth preterm. That’s true even when comparing black and white mothers who had achieved the same level of education, which Catov said is “a pretty potent marker” of socioeconomic status.

The information comes from a new study from the University of Pittsburgh, published last week in the journal Pediatrics, which looked at children who continued to receive pediatric care from UPMC through their second birthday.